Described herein are catalytic compositions capable of converting nitriles to amides, and alkenes to primary alcohols.
A general procedure for obtaining carboxamides [RC(O)NH.sub.2 ] is to effect hydration of the corresponding nitriles with suitable acid or base catalysts. This is shown in the following equation: ##STR1##
A carboxamide of considerable commercial importance is acrylamide. The latter is utilized in polymer form in paper production, waste water recovery, as well as oil recovery processes, and is favorably employed in numerous other commercial applications. Because of undesirable competing side reactions arising from the use of heterogenous catalysts such as reduced copper metal oxides there is presently considerable effort directed toward identifying catalysts capable of effecting regioselective hydrolysis of acrylonitrile to yield acrylamide. For example, homogeneous catalysts consisting of noble metals, particularly platinum, yield mixtures of chemicals derived from the reaction with acrylonitrile. The following equation reveals that hydration of acrylonitrile with a conventional platinum catalyst yields acrylamide, beta-cyanoethanol, and beta-dicyanoethylether: ##STR2##
Hydration of the unsaturated double bond associated with acrylonitrile produces beta-cyanoethanol, while beta-dicyanoethylether results from the addition reaction of the hydroxyl group on beta-cyanoethanol to the double bond of acrylonitrile. Attempts to prevent the formation of undesirable side products have met with limited success.
An additional undesirable feature associated with the catalytic conversion of amides from nitriles is the necessity to perform the reaction at elevated temperatures. For example, Arnold and Bennett, in the Journal of Organometallic Chemistry, (1980, 199:119-135), show several platinum and palladium organo tertiary phosphine compounds with appreciable catalytic activity only at temperatures above 80.degree. C.
A second class of nitriles that are difficult to hydrate using conventional synthetic schemes are those that display an ester functionality. Members of this class, including precursors to pyridones, are chemical intermediates useful for preparing a variety of medicinals. Thus, it is desirable to discover alternative methods of generating these compounds.
It is apparent from the foregoing discussion that it is desirable to have a catalyst that converts nitriles to amides without the production of significant side products, and moreover, that functions adequately at low temperatures.
There are numerous other chemical reactions where the commercial feasibility of obtaining the products derived therefrom would be greatly increased if suitable catalysts were available. An example is the hydration of terminal unsaturated double bonds associated with various classes of hydrocarbon molecules. A specific instance whereby such catalysts would be useful is the hydration of alkenes to produce primary alcohols. While catalysts such as phosphoric acid, transition metal oxides, zeolites, and clays do catalyze the hydration of alkenes, the products are generally not primary alcohols because the reactions follow Markownikoff's rule, or if they are produced at all, the yields are too low to be commercially appealing. Antimarkownikoff addition reactions are known such as hydroboration, but these are not catalytic.
Because straight-chain primary alcohols have extensive commercial use, particularly in surfactants, plasticizers, and the like, it would be commercially advantageous to have catalysts capable of producing these substances selectively, and under mild reaction conditions.